IL4 and asthma: The therapeutic roles of TCs in the respiratory tract were hypothesized from the beginning, and one important role in the reduction of inflammation in experimental astma was demonstrated after transplantation of TCs, which could improve allergen-induced asthma by obviously inhibiting airway inflammation and airway hyper-responsiveness preclinically, with the down-regulation of Th2-related cytokine IL-4, transcription factor GATA-3 and Th2 cell differentiation, and the up-regulation of Th1-related cytokine IFN-γ, transcription factor T-bet and Th1 cell proliferation in asthma[25].